The Thermal Oxide Reprocessing Plant at Sellafield - Lessons Learned from 10 Years of Hot Operations and their Applicability to the DOE Environmental Management Program
- BNG America, 2345 Stevens Drive, Richland, WA 99354 (United States)
- British Nuclear Group, Thorp Technical Department, Sellafield, Cumbria, CA20 1PG (United Kingdom)
The Thermal Oxide Reprocessing Plant (Thorp) at Sellafield in northwest England is a $4 billion integrated plant that takes irradiated fuel from worldwide Light Water Reactors and UK Gas-Cooled Reactors and separates the uranium and plutonium from the fission products so that the latter can be vitrified and safely stored. The uranium and plutonium are further separated so that the uranium can be recycled as new reactor fuel, either by itself or in combination with the plutonium as Mixed Oxide (MOX) fuel. Thorp concentrates in excess of 99% of the radioactivity in the irradiated fuel into the vitrified waste product and produces a 40-fold reduction in high active waste volume to be stored, in comparison with direct disposal of the fuel. Thorp incorporates a range of design and operational principles developed over the 50 year history of the Sellafield site. These include the extensive use of no-moving part, no-maintenance equipment in contact with radioactive material, located in shielded 'dark cells' where entry is not expected through the life of the plant. These cells are nevertheless provided with comprehensive secondary containment, instruments, wash-down and recovery systems, and access for cameras and potentially also for remote repair equipment. These arrangements were found to be required during an unusual incident identified in early 2005 when approximately 83 m{sup 3} of highly active liquid escaped from primary tank containment into the secondary containment formed by the dark cell and its stainless steel liner. Although a serious incident, the secondary containment and the in-cell design provisions worked exactly as designed and the liquid was recovered by mid 2005 with no releases to the environment and no member of the workforce or public affected. The ability to access and clean dark cells means that repairs are possible and the large capital asset is thus protected. The enquiry that followed this incident identified issues with carry-through of late design changes into operations and with the training and mind-set of the operators, the latter leading to a later than ideal identification of the loss of primary containment. This paper describes Thorp, its design and operational principles, its performance over the last 10 years and provides details of the loss of containment incident. It draws lessons from this incident and looks at how these could be applied to assist the current DOE Environmental Management (EM) program and its large waste treatment plants at Hanford and Savannah River. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 13023, Tucson, AZ, 85732-3023 (United States)
- OSTI ID:
- 21210735
- Report Number(s):
- INIS-US-09-WM-06482; TRN: US09V1163081197
- Resource Relation:
- Conference: Waste Management 2006 Symposium - WM'06 - Global Accomplishments in Environmental and Radioactive Waste Management: Education and Opportunity for the Next Generation of Waste Management Professionals, Tucson, AZ (United States), 26 Feb - 2 Mar 2006; Other Information: Country of input: France; 7 refs
- Country of Publication:
- United States
- Language:
- English
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